The document is a comprehensive overview of lesser-known features of the Ruby programming language, detailing various methods and functionalities such as string manipulations, benchmarking, and option parsing. It highlights the use of Ruby's standard library, including structs, array manipulations, and profiling tools, while also providing code examples for clarity. The author acknowledges contributions from the community and encourages further exploration of these features.

1. HIDDEN TREASURES
of
RUBY
@MrJaba - iprug - 6th Dec 2011

2. Whistlestop tour through the lesser
known/obscure features of Ruby

3. Ruby has a
HUGE
standard library

4. Have you heard of?
Struct
OpenStruct
OptionParser
Abbrev
Benchmark
Find
English

5. Did you know about?
String#squeeze
String#count
String#tr
Kernel#Array
Kernel#trace_var

6. This is just for FUN

7. Core Ruby

8. STRING
#squeeze
“Uh oh the cat sat on the keeeeeeeeeee”.squeeze
=>
“Uh oh the cat sat on the ke”
“oh craaaapppp my aaappp keys are bloody
broken”.squeeze(“ap”)
=>
“oh crap my ap keys are bloody broken”

9. STRING
#count
“FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS.”
How many F’s are there?

10. STRING
#count
“FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS.”.count(“F”)
=>
6

11. STRING
#count
“how many woods would a wood chuck chuck if a
wood chuck could chuck wood?”.count(“a-z”, “^u”)
=>
52

12. “DYTSMH”
.tr(“DYTSMH”, “STRING”)
“STRING”
.tr(“R-T”, “F”)
“FFFING”

13. KERNEL
#Array
yesthat’sacapitalletter
Array(1..3) + Array(args[:thing])
=
[1,2,3, “Thing”]
thing.to_a
=
NoMethodError: undefined method `to_a' for
thing:String

14. KERNEL
#at_exit
at_exit { p ObjectSpace.count_objects }
=
{:TOTAL=31479, :FREE=4687, :T_OBJECT=1442, :T_CLASS=859, :T_MODULE=32, :T_FLOAT=7,
:T_STRING=18190, :T_REGEXP=168, :T_ARRAY=3657, :T_HASH=134, :T_STRUCT=1, :T_BIGNUM=2,
:T_FILE=6, :T_DATA=1210, :T_MATCH=100, :T_COMPLEX=1, :T_NODE=949, :T_ICLASS=34}
at_exit {
loop do
p “unkillable code!”
end }

15. KERNEL
#set_trace_func
class Cheese
def eat
p “om nom nom”
end
end
set_trace_func proc {|event, file, line, id, binding, classname|
p “#{event}, #{file}, #{line}, #{id}, #{binding}, #{classname}”
}
=
c-return, cheese.rb, 9, set_trace_func, #Binding:0x007fe11b84e488, Kernel
line, cheese.rb, 11, , #Binding:0x007fe11b84e1e0,
c-call, cheese.rb, 11, new, #Binding:0x007fe11b84dfb0, Class
c-call, cheese.rb, 11, initialize, #Binding:0x007fe11b84dc90, BasicObject
c-return, cheese.rb, 11, initialize, #Binding:0x007fe11b84da38, BasicObject
c-return, cheese.rb, 11, new, #Binding:0x007fe11b84d808, Class
line, cheese.rb, 12, , #Binding:0x007fe11b84d5d8,
call, cheese.rb, 2, eat, #Binding:0x007fe11b84d3a8, Cheese
line, cheese.rb, 3, eat, #Binding:0x007fe11b84d150, Cheese
c-call, cheese.rb, 3, p, #Binding:0x007fe11b84cef8, Kernel
c-call, cheese.rb, 3, inspect, #Binding:0x007fe11b84ccc8, String
c-return, cheese.rb, 3, inspect, #Binding:0x007fe11b84ca48, String
om nom nom
c-return, cheese.rb, 3, p, #Binding:0x007fe11b84c7f0, Kernel
return, cheese.rb, 4, eat, #Binding:0x007fe11b84c5c0, Cheese

16. Struct
Point = Struct.new :x, :y do
def distance(point)
Math.sqrt((point.x - self.x) ** 2 +
(point.y - self.y) ** 2)
end
end

17. Why? Struct
Quickly define a class with a few known fields
Automatic Hash key
Mitigate risk of spelling errors on field names

18. Ruby
STANDARD
LIBRARY

19. 113 Packages

20. OptionParser
require ‘optparse’
options = {}
parser = OptionParser.new
parser.on(-i, --ipswich, description of IP) {|val| options[:ipswich] = val }
parser.on(-r=ARG, --ruby, Mandatory Argument) {|val| options[:ruby] = val }
parser.on(-u=[ARG], --user, Optional Argument) {|val| options[:user] = val }
parser.on(-g=ARG, --group, Integer, Type cast Argument) {|val| options[:group] = val }
unmatched = parser.parse(ARGV)
puts parser.to_s
puts options are #{options.inspect}
puts unmatched are #{unmatched.inspect}

21. Abbrev
require ‘abbrev’
Abbrev::abbrev(['Whatever'])
{Whateve=Whatever, Whatev=Whateve
Whate=Whatever, What=Whatever,
Wha=Whatever, Wh=Whatever,
W=Whatever, Whatever=Whatever}
Thereisno“whatevs”inthere!

22. Benchmark
require ‘benchmark’
puts Benchmark.measure { calculate_meaning_of_life }
=
0.42 0.42 0.42 ( 4.2)
ElapsedRealTime
UserCPU Sum
SystemCPU
Benchmark.bmbm do |x|
x.report(sort!) { array.dup.sort! }
x.report(sort) { array.dup.sort }
end
=
user system total real
sort! 12.959000 0.010000 12.969000 ( 13.793000)
sort 12.007000 0.000000 12.007000 ( 12.791000)

23. English
require ‘English’
$ERROR_INFO $! $DEFAULT_OUTPUT $
$ERROR_POSITION $@ $DEFAULT_INPUT $
$FS $; $PID $$
$FIELD_SEPARATOR $; $PROCESS_ID $$
$OFS $, $CHILD_STATUS $?
$OUTPUT_FIELD_SEPARATOR $, $LAST_MATCH_INFO $~
$RS $/ $IGNORECASE $=
$INPUT_RECORD_SEPARATOR $/ $ARGV $*
$ORS $ $MATCH $
$OUTPUT_RECORD_SEPARATOR $ $PREMATCH $`
$INPUT_LINE_NUMBER $. $POSTMATCH $'
$NR $. $LAST_PAREN_MATCH $+
$LAST_READ_LINE $_

24. Find
require ‘find’
Find.find(“/Users/ET”) do |path|
puts path
Find.prune if path =~ /hell/
end
= Geddit?
/Users/ET/phone
/Users/ET/home

25. Profiler__
require ‘profiler’
Profiler__::start_profile
complicated_method_call
Profiler__::stop_profile
Profiler__::print_profile($stdout)
% cumulative self self total
time seconds seconds calls ms/call ms/call name
0.00 0.00 0.00 1 0.00 0.00 Integer#times
0.00 0.00 0.00 1 0.00 0.00 Object#complicated_method_call
0.00 0.01 0.00 1 0.00 10.00 #toplevel

26. RSS
require ‘rss/2.0’
response = open(http://feeds.feedburner.com/MrjabasAdventures).read
rss = RSS::Parser.parse(response, false)
rss.items.each do |item|
p item.title
end

27. MiniTest
require ‘minitest/autorun’
describe Cheese do
before do
@cheddar = Cheese.new(“cheddar”)
end
describe when enquiring about smelliness do
it must respond with a stink factor do
@cheddar.smelliness?.must_equal 0.9
end
end
end
Provides:
Specs Mocking Stubbing Runners Benchmarks

28. Thank you to
everyone involved in
Ruby!